A camshaft adjusting apparatus of said type is known from DE 101 03 876 A1/U.S. Pat. No. 6,553,951 B2 and from US 2006/0213471 A1. In said documents, a housing component which can be driven by the motor of an internal combustion engine, and a rotor component which is connected to a camshaft for conjoint rotation therewith, are arranged so as to be rotatable relative to one another. To adjust a relative rotational phase angle between the rotor component and housing component, these are operatively connected to one another by means of a plurality of pressure spaces which are in each case divided, by a vane part connected to the rotor component for conjoint rotation therewith, into two pressure chambers which can be charged with pressure medium and which act counter to one another. The housing component and the rotor component can be mechanically coupled to one another by means of a blocking mechanism which can be actuated using pressure medium. The pressure chambers and the locking device have a pressure medium connection to a control valve for regulating the pressure medium supply to and from them. A disadvantage of said embodiment is the fact that, during an adjustment of the relative rotational phase angle between the rotor component and housing component, as a result of a periodic oscillation of the vane parts in the adjusting direction caused by the fluctuating torques acting on the camshaft, a vacuum may be generated in the pressure chambers to be filled, which vacuum can propagate via the pressure medium connection into the locking mechanism. If the locking pressure of the locking mechanism is undershot, this may lead, during an adjustment process, to an inadvertent locking or partial locking of the camshaft adjusting apparatus, and to a malfunction. This effect is promoted in particular by low pressure medium temperatures prevailing in the pressure medium system with high viscosity of the pressure medium, and/or by a large suction volume of the camshaft adjusting apparatus, that is to say if, for adjustment, a pressure medium volume flow is required which is large in relation to the adjustment angle.